A computer-based Eye Movement Controlled Display System is being developed, which is capable of modifying the pattern on a cathode-ray tube on the basis of the subject's direction of gaze, and which is capable of keeping a complete record of the subject's eye movements. This system is being used to investigate perceptual and psycholinguistic processes in skilled reading. Questions being studied include the size of the region from which visual information is acquired during a fixation in reading, the lag from the time a word is encountered until that information is processed at different levels, and whether fixation duration data can be used to test theories of language processing in reading.